Revert of [handles] Sanitize Handle and friends. (patchset #5 id:180001 of...

Revert of [handles] Sanitize Handle and friends. (patchset #5 id:180001 of https://codereview.chromium.org/1128533002/)

Reason for revert:
[Sheriff] Still breaks mac asan:
http://build.chromium.org/p/client.v8/builders/V8%20Mac64%20ASAN/builds/2066

Original issue's description:
> [handles] Sanitize Handle and friends.
>
> Bunch of cleanups to allow us to get rid of handles-inl.h at some
> point (in the not so far future); but more importantly to sanitize uses
> of handles and prepare for handle canonicalization support.
>
> R=yangguo@chromium.org
>
> Committed: https://crrev.com/3283195d0408333cce552cf4087577e6f41054e5
> Cr-Commit-Position: refs/heads/master@{#28222}
>
> Committed: https://crrev.com/d940c6d3bcc227b459cb4123d9a8332d9ed0d5f8
> Cr-Commit-Position: refs/heads/master@{#29666}

TBR=yangguo@chromium.org,bmeurer@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true

Review URL: https://codereview.chromium.org/1235253007

Cr-Commit-Position: refs/heads/master@{#29669}

src/api.cc

@@ -3797,8 +3797,7 @@ MaybeLocal<String> v8::Object::ObjectProtoToString(Local<Context> context) {
                                  isolate, self, toStringTag).ToHandle(&tag);
     RETURN_ON_FAILED_EXECUTION(String);
     if (tag->IsString()) {
-      class_name = Utils::OpenHandle(*handle_scope.Escape(
-          Utils::ToLocal(i::Handle<i::String>::cast(tag))));
+      class_name = i::Handle<i::String>::cast(tag).EscapeFrom(&handle_scope);
     }
   }
   const char* prefix = "[object ";

src/api.h

@@ -308,6 +308,17 @@ OPEN_HANDLE_LIST(DECLARE_OPEN_HANDLE)
 };
 
 
+template <class T>
+v8::internal::Handle<T> v8::internal::Handle<T>::EscapeFrom(
+    v8::EscapableHandleScope* scope) {
+  v8::internal::Handle<T> handle;
+  if (!is_null()) {
+    handle = *this;
+  }
+  return Utils::OpenHandle(*scope->Escape(Utils::ToLocal(handle)), true);
+}
+
+
 template <class T>
 inline T* ToApi(v8::internal::Handle<v8::internal::Object> obj) {
   return reinterpret_cast<T*>(obj.location());

src/handles-inl.h

 // Copyright 2006-2008 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
+//
 
 #ifndef V8_HANDLES_INL_H_
 #define V8_HANDLES_INL_H_
@@ -13,8 +14,72 @@
 namespace v8 {
 namespace internal {
 
-HandleBase::HandleBase(Object* object, Isolate* isolate)
-    : location_(HandleScope::CreateHandle(isolate, object)) {}
+template<typename T>
+Handle<T>::Handle(T* obj) {
+  location_ = HandleScope::CreateHandle(obj->GetIsolate(), obj);
+}
+
+
+template<typename T>
+Handle<T>::Handle(T* obj, Isolate* isolate) {
+  location_ = HandleScope::CreateHandle(isolate, obj);
+}
+
+
+template <typename T>
+inline bool Handle<T>::is_identical_to(const Handle<T> o) const {
+  // Dereferencing deferred handles to check object equality is safe.
+  SLOW_DCHECK(
+      (location_ == NULL || IsDereferenceAllowed(NO_DEFERRED_CHECK)) &&
+      (o.location_ == NULL || o.IsDereferenceAllowed(NO_DEFERRED_CHECK)));
+  if (location_ == o.location_) return true;
+  if (location_ == NULL || o.location_ == NULL) return false;
+  return *location_ == *o.location_;
+}
+
+
+template <typename T>
+inline T* Handle<T>::operator*() const {
+  SLOW_DCHECK(IsDereferenceAllowed(INCLUDE_DEFERRED_CHECK));
+  return *bit_cast<T**>(location_);
+}
+
+template <typename T>
+inline T** Handle<T>::location() const {
+  SLOW_DCHECK(location_ == NULL ||
+              IsDereferenceAllowed(INCLUDE_DEFERRED_CHECK));
+  return location_;
+}
+
+#ifdef DEBUG
+template <typename T>
+bool Handle<T>::IsDereferenceAllowed(DereferenceCheckMode mode) const {
+  DCHECK(location_ != NULL);
+  Object* object = *bit_cast<T**>(location_);
+  if (object->IsSmi()) return true;
+  HeapObject* heap_object = HeapObject::cast(object);
+  Heap* heap = heap_object->GetHeap();
+  Object** handle = reinterpret_cast<Object**>(location_);
+  Object** roots_array_start = heap->roots_array_start();
+  if (roots_array_start <= handle &&
+      handle < roots_array_start + Heap::kStrongRootListLength &&
+      heap->RootCanBeTreatedAsConstant(
+        static_cast<Heap::RootListIndex>(handle - roots_array_start))) {
+    return true;
+  }
+  if (!AllowHandleDereference::IsAllowed()) return false;
+  if (mode == INCLUDE_DEFERRED_CHECK &&
+      !AllowDeferredHandleDereference::IsAllowed()) {
+    // Accessing cells, maps and internalized strings is safe.
+    if (heap_object->IsCell()) return true;
+    if (heap_object->IsMap()) return true;
+    if (heap_object->IsInternalizedString()) return true;
+    return !heap->isolate()->IsDeferredHandle(handle);
+  }
+  return true;
+}
+#endif
+
 
 
 HandleScope::HandleScope(Isolate* isolate) {
@@ -71,7 +136,7 @@ Handle<T> HandleScope::CloseAndEscape(Handle<T> handle_value) {
   CloseScope(isolate_, prev_next_, prev_limit_);
   // Allocate one handle in the parent scope.
   DCHECK(current->level > 0);
-  Handle<T> result(value, isolate_);
+  Handle<T> result(CreateHandle<T>(isolate_, value));
   // Reinitialize the current scope (so that it's ready
   // to be used or closed again).
   prev_next_ = current->next;
@@ -86,7 +151,7 @@ T** HandleScope::CreateHandle(Isolate* isolate, T* value) {
   DCHECK(AllowHandleAllocation::IsAllowed());
   HandleScopeData* current = isolate->handle_scope_data();
 
-  Object** cur = current->next;
+  internal::Object** cur = current->next;
   if (cur == current->limit) cur = Extend(isolate);
   // Update the current next field, set the value in the created
   // handle, and return the result.
@@ -125,7 +190,6 @@ inline SealHandleScope::~SealHandleScope() {
 
 #endif
 
-}  // namespace internal
-}  // namespace v8
+} }  // namespace v8::internal
 
 #endif  // V8_HANDLES_INL_H_

src/handles.cc

@@ -9,34 +9,6 @@
 namespace v8 {
 namespace internal {
 
-#ifdef DEBUG
-bool HandleBase::IsDereferenceAllowed(DereferenceCheckMode mode) const {
-  DCHECK_NOT_NULL(location_);
-  Object* object = *location_;
-  if (object->IsSmi()) return true;
-  HeapObject* heap_object = HeapObject::cast(object);
-  Heap* heap = heap_object->GetHeap();
-  Object** roots_array_start = heap->roots_array_start();
-  if (roots_array_start <= location_ &&
-      location_ < roots_array_start + Heap::kStrongRootListLength &&
-      heap->RootCanBeTreatedAsConstant(
-          static_cast<Heap::RootListIndex>(location_ - roots_array_start))) {
-    return true;
-  }
-  if (!AllowHandleDereference::IsAllowed()) return false;
-  if (mode == INCLUDE_DEFERRED_CHECK &&
-      !AllowDeferredHandleDereference::IsAllowed()) {
-    // Accessing cells, maps and internalized strings is safe.
-    if (heap_object->IsCell()) return true;
-    if (heap_object->IsMap()) return true;
-    if (heap_object->IsInternalizedString()) return true;
-    return !heap->isolate()->IsDeferredHandle(location_);
-  }
-  return true;
-}
-#endif
-
-
 int HandleScope::NumberOfHandles(Isolate* isolate) {
   HandleScopeImplementer* impl = isolate->handle_scope_implementer();
   int n = impl->blocks()->length();
@@ -95,7 +67,7 @@ void HandleScope::DeleteExtensions(Isolate* isolate) {
 void HandleScope::ZapRange(Object** start, Object** end) {
   DCHECK(end - start <= kHandleBlockSize);
   for (Object** p = start; p != end; p++) {
-    *reinterpret_cast<Address*>(p) = kHandleZapValue;
+    *reinterpret_cast<Address*>(p) = v8::internal::kHandleZapValue;
   }
 }
 #endif

test/cctest/test-heap.cc

@@ -973,6 +973,22 @@ TEST(Iteration) {
 }
 
 
+TEST(EmptyHandleEscapeFrom) {
+  CcTest::InitializeVM();
+
+  v8::HandleScope scope(CcTest::isolate());
+  Handle<JSObject> runaway;
+
+  {
+      v8::EscapableHandleScope nested(CcTest::isolate());
+      Handle<JSObject> empty;
+      runaway = empty.EscapeFrom(&nested);
+  }
+
+  CHECK(runaway.is_null());
+}
+
+
 static int LenFromSize(int size) {
   return (size - FixedArray::kHeaderSize) / kPointerSize;
 }